I keep getting an error

I’ve authorised it a few times now, and I keep getting the same error on just 1 particular site. It works on other sites that I’ve installed this on. But here’s the error just in case:

Last Error: 2015-08-24 23:26:44: exception 'Google_Auth_Exception' with message 'Error fetching OAuth2 access token, message: 'invalid_grant: Code was already redeemed.'' in /home/yoursmarterhome/htdocs/wp-content/plugins/google-analytics-dashboard-for-wp/tools/src/Google/Auth/OAuth2.php:126
Stack trace:
#0 /home/yoursmarterhome/htdocs/wp-content/plugins/google-analytics-dashboard-for-wp/tools/src/Google/Client.php(133): Google_Auth_OAuth2->authenticate('4/iElsFQuVSQvUo...')
#1 /home/yoursmarterhome/htdocs/wp-content/plugins/google-analytics-dashboard-for-wp/admin/settings.php(725): Google_Client->authenticate('4/iElsFQuVSQvUo...')
#2 [internal function]: GADWP_Settings::general_settings('')
#3 /home/yoursmarterhome/htdocs/wp-includes/plugin.php(503): call_user_func_array(Array, Array)
#4 /home/yoursmarterhome/htdocs/wp-admin/admin.php(236): do_action('toplevel_page_g...')
#5 {main}
ResponseHttpCode:400

Any ideas how I can fix it?

Thanks.

https://www.ads-software.com/plugins/wp-google-analytics/